Each year more than 455,000 patients survive an episode of acute respiratory failure (ARF) that required endotracheal intubation with mechanical ventilation. Nearly half of these ARF survivors suffer from dysphagia, or the inability to effectively transfer food and liquid from their mouth to stomach. As a result of their dysphagia, ARF survivors are more likely to aspirate and develop pneumonia, have a percutaneous feeding tube placed, and require admission to a long term care facility. To avoid these deleterious effects of aspiration, the resumption of oral nutrition is sometimes inappropriately delayed, subsequently prolonging the need for enteral tube feeding, compounding caregiver burden, causing patient dissatisfaction, and increasing health-related costs. Therefore, improving the ability to easily and accurately diagnose aspiration in ARF survivors would reduce the frequency and severity of aspiration and limit the consequences associated with delaying oral nutrition. In most intensive care units, speech language pathologists (SLPs) determine when ARF survivors can resume oral feeding, and they rely upon the bedside swallow evaluation (BSE) to detect aspiration. Unfortunately, there are currently no BSE-based clinical prediction rules (CPRs) that accurately diagnose aspiration in ARF survivors. In addition, the mechanisms responsible for the development of aspiration in ARF survivors are essentially unknown. This proposal will develop a BSE-based non-invasive CPR to diagnose aspiration in ARF survivors while also unraveling the mechanisms responsible for aspiration. We will conduct a multi-center observational cohort study with two specific aims: 1) To develop a BSE-based non-invasive clinical prediction rule (CPR) that will accurately and efficiently diagnose aspiration in ARF survivors and 2) To identify abnormalities in laryngeal structure and swallowing physiology that are associated with aspiration in ARF survivors. Ultimately, these results will pave the way for the development of novel and targeted therapies to prevent and treat aspiration.